Return baffle for flue doors



Aug. 4, 1931. F. w. IHVOSLEF 1,817,150

RETURN BAFFLE FOR FLUE DOORS Filed Oct. 18. 1930 mafia: 4 4

Patented Aug. 4, 1931 UNITED STATES PATENT OFFHTE FREDR-IK W. I-IVOSLEF,OF KOELEB,

KOHLER, \VISCGNSIIQ', A. CORPORATIGII OF \VISGONSIN' RETUR-h BAFFLE FORBLUE DOORS Application filed Qctober 18, 1939.

This invention has for its object to provide the flue door of a boileror furnace with a return battle for deflectlng flue gases in thedirection of turn of the flue passageways at that point so as tocontribute to the streamline effect and thus facilitate the movement ofthe gases and avoid the production of corners or projections causingeddy currents.

Another object of the invention is to make such a baflie of durable andinxepensive construction and capable of secure and readv attachment tothe flue door and sei protect the flue door from overhcatil WVith theabove and other objects in view the invention consists in the returnbaflle for flue doors as herein claimed and all equivalents.

Referring to the accompanying drawings, in which like characters ofreference indicate the same parts in different views,

Fig. 1 is a sectional plan view of a boiler through the flue doorthereof showing a battle constructed in accordance with this invention;

Fig. 2 is a vertical sectional view on the plane of line 22 of Fig. 1,and

Fig. 3 is an inner face view of the baflle itself.

In these drawings, 10 indicates a sectional boiler of a usual typehaving forwardly directed side flues 11, and a rearwardly directedcentral return flue 12 with a common flue space 18 in the front sectionforming return bends connecting the side flues with the central flue andgiving access to the flue spaces for cleaning through the flue door 14.

It is common practice to provide the back of the flue door withprotecting plates of various types to prevent excessive loss of heatthrough the flue door and the purpose of this invention is to utilizesuch a protecting plate as a baffle conforming with the streamline ofthe flow of gases in making the return bend from both side flues to thecentral return flue. To this end the protecting plate constitutes abaflie 15, which is preferably an iron casting having two parallelcylindrically convex deflecting members 16 Serial No. 469,584.

with top and bottom rearwardly extending flanges 17 on their inner facesand with top and bottom forwardly extending flanges 18 on their outerfaces.

This bafl'le is secured to the back of the flue door 14: by havingopenings 19 at approximately tne middle of the deflecting members 16 toreceive lugs 20 projecting from the back of the flue door, as best seenin Fig. 2. I Slight projections or bosses 21 formed on the battle aboveand below the openings 19 to form bearing points for contacting with theinner wall of the flue door and the baiiie is held in contact at suchpoints by the action of wedge pins 22 driven through vertical openingsin the lugs 20 and guided in beveled notches 23 above and below theopenings 19 and resting on projections 24. The baflle is thus securelymounted on the back of the flue door and, except for its points ofcontact therewith, is spaced therefrom and forms a guard for preventingoverheating ofthe door.

The principal function of the baflie, however, is that of constitutingdeflecting surfaces in the path of the forwardly travel ling gases fromthe side flues 11 for directing them inwardly to the central return flue12 with a minimum amount of resistance due to eddy currents. The doubleconvex deflector conforms with the path of travel of the gases topresent a streamline guide to exclude pockets or corners in which eddycurrents may beformed and consequently the flow of gas is facilitated,improving the draft and avoiding waste of heat.

The manner of mounting the batfle on the flue door makes for a permanentconnection that will resist the action of heat and that may be readilyreleased at any time that it may be necessary or desirable and still theflue door is not marred by the presence of bolt holes and consequentlymay be enameled to present a neat and ornamental appearance.

What I claim as new and desire to secure by Letters Patent is:

1. A battle for flue doors comprising a plate having means for attachingit to and spacing it from the inner side of a flue door,

said plate being of curved form for de- V fleeting flue gases from oneflue to another. 7 7

2. A baffle for'flue doors Comprising a plate forming a pair ofcontiguous concave surfaces and provided With, means for at.- taching itto and spacing it from the inner side of a flue door, said surfacesserving to conform With the direction ofcurrent of gases from side fluesto a central return'flue to complete a streamline guide-therefor.-

3. In a boiler or furnace having side flues and a central return flue, aflue door giving access thereto, and a baffle comprising a piateattached to and spaced from the inner side of'tlie door and formingapair of contiguous concave surfaces conforming with the path of flow.of-gasfromfthe' side flue V r to the central return flue'to form-astreanrline guide-therefor. I

4. In a boiler or furnace "having side flues and "a central return flue,a flue door for controlling access to a, bafiie comprising a platehaving two 7 contiguous cylindrical concave-surfaces at the rear, topand bottom flanges extending rearWardly-from said sur- I 1. faces, topand bottom'fianges extending for- V Wardly from the junction betweensaidsurthrough openings in the cylindrical surfaces,

faces, and means for securing the plate to thejinnerside of the fluedoor.

5. In a boileror furnace, a flue door, a baffle comprising -a;platehaving a pair of vcontiguous cylindrical concave rearwardly directedsurfaces, a pair of "lugs formed on the 1111161 slde .of the flue doorenter ng I spacing projections formed on the baflle ture.

plate and bearing onfthe backof theiiue door, and pinsi'; extendingthrough openings in thelugsand holding-it in place. 7

.QIn testimony whereof ;I afiixfmy signa r I FREDRiK W. .irvosLEF.

engaging the 'ba'flle: for

